Re: [PATCH/7.6] Fix wrong release (maybe crash GDB) in build_target_command_list

[Hui Zhu <teawater@gmail.com>]

On Wed, Apr 24, 2013 at 10:30 PM, Tom Tromey <tromey@redhat.com> wrote:
>>>>>> "Hui" == Hui Zhu <teawater@gmail.com> writes:
>
> Hui> 2013-04-24  Hui Zhu  <hui@codesourcery.com>
>
> Hui>    * breakpoint.c (build_target_command_list): Change loc->cond_bytecode
> Hui>    to loc->cmd_bytecode.
>
> Is it possible to make a test case for this?

I tried but looks free conditions cannot crash GDB.  :(

>
> The patch looks good.
>
> I am curious about this code in build_target_command_list:
>
>               aexpr = parse_cmd_to_aexpr (bl->address,
>                                           loc->owner->extra_string);
>               loc->cmd_bytecode = aexpr;
>
>               if (!aexpr)
>                 continue;
>
> The "continue" seems to mean that null_command_or_parse_error will not
> be set in the "parse error" case.

I think it is right, because even if one of breakpoint loc doesn't
have commands.  GDB still need send other commands to target.

>
> Also, parse_cmd_to_aexpr calls 'error' in a few spots but then in
> another spot is careful not to.  This seems somewhat odd.

This function looks have something still not right.  I am just working
on 15180 to make it better.

On 04/24/2013 09:29 PM, Hui Zhu wrote:
-             if (!loc->cond_bytecode)
+             if (!loc->cmd_bytecode)

Nit:          "if (loc->cmd_bytecode == NULL)" is better.

Fixed.

Thanks,
Hui

>
> Tom

2013-04-24  Hui Zhu  <hui@codesourcery.com>

	* breakpoint.c (build_target_command_list): Change loc->cond_bytecode
	to loc->cmd_bytecode.

--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -2343,11 +2343,11 @@ build_target_command_list (struct bp_loc
 	    {
 	      /* Only go as far as the first NULL bytecode is
 		 located.  */
-	      if (!loc->cond_bytecode)
+	      if (loc->cmd_bytecode == NULL)
 		return;

-	      free_agent_expr (loc->cond_bytecode);
-	      loc->cond_bytecode = NULL;
+	      free_agent_expr (loc->cmd_bytecode);
+	      loc->cmd_bytecode = NULL;
 	    }
 	}
     }